Mortar ammunition



Dec. 6, 1966 H. STADLER ETAL 3,

MORTAR AMMUNITION Filed April 15, 1965 HER INVENTORS HANS STADLER HEINZ GAWLICK BY 8km 6?,

ATTORNE United States Patent Ofiice meme; ffifiii The present invention relates to mortar ammunition, and more particularly to fired mortar cartridges for use "in maneuvers or practice firings.

The German patent application D 41,704 Ic/ 72d and the corresponding U.S. application S.N. 370,820, filed May 28, 1964, by Hans Stadler et al, for a Cartridge relates to a fired cartridge for mortars and proposes to provide in the propellant charge of the cartridge a central chamber parallel to the cartridge axis which extends over the entire length of the propellant charge. This chamber may thereby have a cylindrical or star-shaped cross section or also any other cross section and is made appropriately of an easily destructible or breakable material, for example, of thin paper, plastic foil, or also of a powder foil.

This construction has proved very satisfactory under the prerequisite condition that the combustion space of the propellant charge is closed off at its forward end face and a possibility is provided for the combustion gases of the propellant charge by means of lateral radial bores arranged in the cartridge chamber to punch out by reason of the pressure thereof the case walls within the area of these bores and then to escape through these bores into a second larger combustion space.

Also in case that no lateral escape into the larger combustion space is possible for the combustion gases but instead these combustion gases are constrained to flow out in the direction of the axis of the barrel of the weapon, the aforementioned prior art construction achieved satisfactory results, and more particularly when the combustion space is closed ofif in the forward direction by a shell whose weight amounts to about 50 to 500 times the weight of the propellant charge. If, however, the weight of the shell is reduced for purposes of reduction of its flight distance or of its penetrating force, for instance, for maneuver purposes, below the value of about 50 times the weight of the propellant charge or if a larger expansion space is provided between the fired cartridge and the shell for purposes of avoiding an excessively high peak pressure, then the results obtained with the prior art constructions are less satisfactory.

It has now been discovered that this drawback and shortcoming can be eliminated if according to the proposal of the present invention, the propellant charge in the cartridge is provided with a central chamber parallel to the axis which extends from the rear end of the propellant charge over at least 20% and at most 80% of the longitudinal dimension of the propellant charge. Also in this case, the chamber is constructed preferably of circularly shaped cross section, but of course may also be constructed of star-shaped or any other cross section. The chamber may also again in this case be made of an easily breakable and/ or readily destructible material such as, for example, of thin paper, plastic foil or powder foil. It is particularly appropriate if the chamber according to further feature of the present invention is constructed 'as cylindrical plastic case, closed on one side thereof, and if it is secured additionally with its open end by means of a press-fit or force-fit on an extension of a cartridge base receiving within central bore thereof the primer and/or booster charge. In order to assure that the chamber within the propellant charge is completely empty so that the ignition jet is not impaired in its expansion, the open end of the chamber is, according to a further appropriate construction of the present invention, closed off by means of a closure disk preferably of plastic material. A particularly simple and appropriate securing of this closure disk results in that the closure disk together with an outwardly projecting annularly shaped flange of the cartridge base projection engages in an annular groove provided at the open end of the chamber or case.

Accordingly, it is an object of the present invention to provide a cartridge for mortars of the type described above which obviates the shortcomings and drawbacks encountered with the prior art construction during use thereof in maneuvers or for practice firings.

Another object of the present invention resides in the provision of a fired cartridge structure for mortars which assures satisfactory results even though the weight of the shell is less than 50 times the weight of the propellant charge.

A further object of the present invention resides in the provision of a mortar ammunition provided With a cartridge that is so constructed and arranged as to permit a reduction of pressure peaks between the cartridge and the shell without impairment of the satisfactory operational results obtainable thereby.

Still another object of the present invention resides in the provision of a cartridge construction for mortars which achieves all of the aforementioned aims by extremely simple and relatively inexpensive means in such a manner that proper and substantially simultaneous ignition of the propellant charge is assured under all operating conditions.

A still further object of the present invention resides in the provision of a mortar cartridge which can be easily manufactured and assembled utilizing only a minimum of parts.

These and other objects, features, and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, two embodiments in accordance with the present invention, and wherein,

FIGURE 1 is a somewhat schematic axial crosssectional View through a fired cartridge in accordance with the present invention including a practice shell in serted at the forward end which is provided with an expansion space, and

FIGURE 2 is a somewhat schematic axial cross sectional view of a modified embodiment of a fired cartridge in accordance with the present invention, similar to FIGURE 1, with the expansion space displaced toward the shell bottom.

Referring now to the drawing wherein like reference numerals are used throughout the two views to designate like parts, and more particularly to FIGURE 1, the cartridge illustrated therein which is arranged within the barrel 1 is provided with a cartridge case 2. The practice shell 3 having a central recess 4 is inserted into the forward end of the case 2. The case 2 is closed at the rear end thereof by means of a cartridge base 5 which is provided within a central bore 6 with the primer and/or booster charge 7 and with a conventional primer or percussion cap (not shown) located to the rear and in the extension of the charge 7. The cylindrical extension 8 of the cartridge base 5 is provided with a flange-like collar 9 by means of which it engages into the annular groove 13 formed into the rearward end of the chamber or case 12 closed in front thereof and extending over about threequarters of the length of the propellant charge space 11 filled with the propellant charge 10. The case 12 is thereby secured on the extension 8 by a press-fit. The closure disk 14 arranged on the extension 8 which also 3 engages into the groove 13 and is secured therein, prevents that the ignition charge material trickles or seeps into the chamber 12 so that a complete emptiness of the chamber 12 is assured.

According to FIGURE 2, in which the same parts corresponding to those of FIGURE 1 are again designated by the same reference numerals, the case 2 is again closed at its forward end face. A relatively large expansion space 15 is disposed between the front end of the case 2 and the bottom of the shell 3. The chamber 12 extends in this case only over barely two-thirds of the length of the propellant charge 10. Apart from the somewhat different construction of the rear end of the cartridge, the arrangement and construction according to FIGURE 2 corresponds as to the rest with that of FIGURE 1.

While we have shown and described two embodiments in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of numerous changes and modifications as known to a person skilled in the art and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. A cartridge comprising a substantially tubular car tridge case; a base portion closing the rear end of said cartridge case; a hollow propellant charge within said cartridge case; substantially tubular case means defining a substantially axial free expansion chamber for the propellant charge gas extending between to 80% of the entire length of said propellant charge within said hollow propellant charge, said free expansion chamber consisting essentially of gases and being substantially free of any explosive material; a projectile telescopically engaged with the forward end of said cartridge case; said cartridge case and said projectile having interengaging means for normally preventing relative axial movement; and said projectile having central recess means opening rearwardly for providing an additional free expansion chamber for the gases produced by the combustion of said propellant charge.

2. The device of claim 1, wherein said projectile has an additional rearwardly extending portion of reduced diameter, said rearwardly extending portion has a groove, and said cartridge case has an inwardly directed flange engaging with said groove.

3. The device of claim 2, including a relatively small igniting charge in said base portion, said igniting charge and said case means being substantially axially aligned, and means, comprising said expansion chambers, for preventing excessively high peak combustion gas pressures when firing a projectile having a weight less than fifty times the weight of said propellant charge.

4. The device of claim 1, including a relatively small igniting charge in said base portion, said igniting charge and said case means being substantially axially aligned, and means, comprising said expansion chambers, for preventing excessively high peak combustion gas pressures when firing a projectile having a weight less than fifty times the weight of said propellant charge.

5. The device of claim 1, wherein said base portion has a substantially tubular forwardly extending base member, said case means has a substantially tubular rearwardly extending case member being telescopically engaged with said base member; one of said members having a generally radially extending annular slot and the other of said members having a correspondingly formed annular generally radially extending projection engaged within said slot; and including a closure wall entirely closing the rearward end of said case means and being engaged within said slot.

6. The device of claim 5, wherein said projectile has a rearwardly extending portion of reduced diameter, said rearwardly extending portion has a groove, and said cartridge case has an inwardly directed flange engaging with said groove.

7. The device of claim 6, wherein said base portion has a substantially central bore extending the entire length of said base portion through said forwardly extending member, and including a primer contained in the rearward portion of said bore and a booster charge filling the forward portion of said bore.

8. The device of claim 7, wherein said slot and said projections are each annular; including a relatively small igniting charge in said base portion, said igniting charge and said case means being substantially axially aligned, and means, comprising said expansion chamber, for preventing excessively high peak combustion gas pressures when firing a projectile having a weight less than fifty times the weight of said propellant charge.

9. The device of claim 5, wherein said base portion has i a substantially central bore extending the entire length of said base portion through said forwardly extending mem ber, and including a primer contained in the rearward portion of said bore and a booster charge filling the forward portion of said bore.

10. A cartridge, comprising a substantially tubular cartridge case; a base portion closing the rear end of said cartridge case; a hollow propellant charge within said cartridge case; substantially tubular case means defining a substantially axial free expansion chamber for the propelant charge gas extending between 20% to of the entire length of said propellant charge within said hollow propellant charge, said free expansion chamber consisting essentially of gases and being substantially free of any explosive material; said base portion having a substantially tubular forwardly extending base member; said case means having a substantially tubular rearwardly extending case member being telescopically engaged with said base member; one of said members having a generally radially extending slot and the other of said members having a correspondingly formed projection engaging within said slot; and a closure wall entirely closing the rearward end of said case means and being engaged within said slot.

11. The device of claim 10 wherein said slot and said projection are each annular.

12. The device of claim 10, wherein said base portion has a substantially central bore extending the entire length of said base portion through said forwardly extending member, and including a primer contained in the rearward portion of said bore and a booster charge filling the forward portion of said bore.

13. A cartridge, comprising: a generally tubular cartridge case having a forward end and a rearward end; a cartridge base portion substantially closing said rearward end of said cartridge case; a propellant charge within said cartridge case adjacent said base; a generally continuous tubular central chamber case closed at one end and open only at the other end; said chamber case extending substantially over at least about 20% to at most about 80%- of the longitudinal dimension of said propellant charge; said cartridge base having means for receiving a primer cap and said cartridge base having a substantially tubular axial integral forward extension; said chamber case having the other open end telescopically secured by a pressfit on said extension; andsaid chamber case being substantially completely void of propellant compositions.

14. Cartridge for mortars, according to claim 13, including:

closure disk means for closing the open end of said substantially cylindrical case with respect to said base portion.

15. A cartridge according to claim 13, wherein said substantially cylindrical case and said closure disk means essentially consist of plastic material.

16. Cartridge for mortars, comprising:

case means,

propellant charge means within said case means,

and central chamber means within said propellant charge means extending substantially parallelly to the axis of the cartridge,

said chamber means extending from the rear end of said propellant charge means over at least about 20% to at most about 80% of the longitudinal dimension of said propellant charge means, said chamber means being constructed as substantially cylindrical case closed at the forward end thereof,

and a cartridge base portion having a substantially cylindrical central extension, said substantially cylindrical case being secured with the open end thereof by a press-fit on said extension,

and closure disk means for closing the open end of said substantially cylindrical case with respect to said base portion,

said extension being provided with an essentially annularly shaped flange,

and said closure disk means together with said flange engaging into an annularly shaped groove provided in the open end of said case means.

17. A cartridge, comprising: a generally tubular cartridge case having a forward end and a rearward end; a cartridge base portion substantially closing said rearward end of said cartridge case; a propellant charge within said cartridge case adjacent said base; a generally continuous tubular central chamber case closed at one end and open only at the other end; said chamber case extending substantially axially over at least about 20% to at most about 80% of the longitudinal dimension of said propellant charge; said cartridge base having means for receiving a primer cap and said cartridge base having a substantially tubular axial integral forward extension; said chamber case having the other open end secured on said extension; said chamber case being substantially completely void of propellant composition; and closure disc means separate from and independent of the primer cap for closing the open end of said chamber case against said base portion.

l8. Cartridge for mortars, comprising:

case means,

propellant charge means within said case means,

and central chamber means within said propellant charge means extending substantially parallely to the axis of the cartridge,

said chamber means extending from the rear end of said propellant charge means over at least about 20% to at most about of the longitudinal dimension of said propellant charge means,

said chamber means being constructed as substantially cylindrical case of plastic material closed at the forward end thereof,

and a cartridge base portion having a substantially cylindrical central extension, said substantially cylindrical case being secured with the oprn end thereof by a press-fit on :aid extension.

and closure disk means of plastic material for closing the open end of said substantially c lindrical case with respect to said base portion,

said extension being provided with an essentially annularly shaped flange,

and said closure disk means together with said flange engaging into an annularly shaped groove prov d in the open end of said case means.

References Cited by the Examiner UNITED STATES PATENTS 1,438,779 12/1922 Olin 10245 FOREIGN PATENTS 714,545 9/1931 France. 813,397 2/1937 France. 958,434 9/1949 France. 1,347,142 11/1963 France.

14,549 1885 Great Britain.

SAMUEL FEINBERG, Primary Examiner.

ROBERT F. STAHL, Examiner. 

1. A CARTRIDGE COMPRISING A SUBSTANTIALLY TUBULAR CARTRIDGE CASE; A BASE PORTION CLOSING THE REAR END OF SAID CARTRIDGE CASE; A HOLLOW PROPELLANT CHARGE WITHIN SAID CARTRIDGE CASE; SUBSTANTIALLY TUBULAR CASE MEANS DEFINING A SUBSTANTIALLY AXIAL FREE EXPANSION CHAMBER FOR THE PROPELLANT CHARGE GAS EXTENDING BETWEEN 20% TO 80% OF THE ENTIRE LENGTH OF SAID PROPELLANT CHARGE WITHIN SAID HOLLOW PROPELLANT CHARGE, SAID FREE EXPANSION CHAMBER CONSISTING ESSENTIALLY OF GASES AND BEING SUBSTANTIALLY FREE OF ANY EXPLOSIVE MATERIAL; A PROJECTILE TELESCOPICALLY ENGAGED WITH THE FORWARD END OF SAID CARTRIDGE CASE; SAID CARTRIDGE CASE AND SAID PROJECTILE HAVING INTERENGAGING MEANS FOR NORMALLY PREVENTING RELATIVE AXIAL MOVEMENT; AND SAID PROJECTILE HAVING CENTRAL RECESS MEANS OPENING 